The indoor swimming pool at Alversdorf is built in the autumn of 1940. During the Second World War, BKB becomes a crucial company for the war effort of major political significance for energy.
Towards the end of the war, women, foreign workers and prisoners of war keep production going. Even during air raids, work continues under blackout in the briquette factories and carbonisation plant. On February 20, 1944, the administration building is hit by a bomb, killing eight employees.
After the war, the company is occupied by allied troops. BKB's operations are now in the British and Russian occupation zones.